Adjustable crank arm



FIG. 1 is an isometric view of an adjustable crank arm;

FIG. 2 is a right side view thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a back view thereof;

FIG. 5 is a front view thereof;

FIG. 6 is a top view thereof; and,

FIG. 7 is a bottom view thereof.

The broken line showing of the adjustable crank arm is for the purpose of illustrating portions of the article and forms no part of the claimed design. 

CLAIM The ornamental design for an adjustable crank arm, as shown and described. 